The sensing of leads inserted through the holes of a printed circuit board using a remotely located camera within a component insertion machine is disclosed in U.S. patent application Ser. No. 797,322, entitled "Lead Sense System for Component Insertion Machine" filed on Nov. 12, 1985. The disclosed system is premised on analyzing a stored electronic image of the inserted leads. The stored electronic image consists of a matrix of pixel bits representing in binary the image field defined by the focused camera. The analysis consists of examining successive partial rows of pixel bits for the presence of at least two adjacent bits having the same predetermined binary value. The bit adjacency is assumed to indicate the detection of a width of an inserted lead. The bit adjacency criteria must be met for a predetermined number of successive rows of pixel bits before a lead is concluded to be present.
The above analysis is premised on a pixel resolution sufficient to allow for a number of pixels to be dedicated to defining the width of a lead. If the number of pixels per width of lead is not sufficiently high, then the algorithm will not reliably detect the presence of an inserted lead. This happens in particular when using the image analysis system disclosed in the aforementioned U.S. patent application Ser. No. 797,322 for a larger field of focus accommodating many more inserted leads that are to be detected.